Conventionally, toner in the form of fine powder is used as a developer for image formation in the image forming apparatus such as an electrophotographic copying machine, a printer or the like. It is also conventional that toner is supplied from a toner supply container exchangeably set in the image forming apparatus with consumption of the toner in the image forming apparatus.
Since the toner is very fine powder, the toner may scatter around if the handling in the toner supplying operation is not proper. For this reason, it is proposed and implemented to keep the toner supply container set within the image forming apparatus, and the toner is discharged gradually through a small opening.
In such a conventional toner supply container, a structure has been proposed in which a gear for driving a toner stirring and feeding member provided in the toner supply container receives a driving force through a driving connection from a gear provided in the image forming apparatus side.
For example, in Japanese Laid-open Patent Application Hei 3-288875, a toner supply container in the form of a dual cylinder including an inner cylinder and an outer cylinder is proposed, wherein a stirring member is disposed in the inner cylinder, and the outside is provided with a gear for driving the stirring member. When such a toner supply container is inserted into the main assembly of the image forming apparatus in the longitudinal direction thereof, a gear provided in the inner cylinder is engaged with the gear provided in the main assembly side of the image forming apparatus. After the engagement is established, only the outer cylinder is rotated through approx. 90°, by which openings of the outer cylinder and the inner cylinder are aligned with each other, and are also aligned with an opening provided in the main assembly side of the image forming apparatus, thus enable the toner supply or replenishment.
However, in such a conventional example, when the operator inserts the toner supply container into the image forming apparatus in the longitudinal direction of the toner supply container, the teeth of the gear in the toner supply container and the teeth gear in the image forming apparatus side may abut each other. If this occurs, the durability of the gears may deteriorate, or in the worst case, the gear or gears may be broken. Particularly, the gear in the image forming apparatus side repeatedly receives the gear of the toner supply container each time the toner supply container is exchanged or reset, and therefore, the problem of the teeth abutment is significant.
This problem may lead to improper toner supply and to a malfunction which requires interruption of the image formation.